Electric switch



Feb. 12 1924.

E. M. HEWLETT ELECTRIC SWITCH Filed Oct 51 1918.

Inventor u i m e t mi by c Patented Feb. 12, 1924.

UNITED STATES PATENT OFFICE.

EDWARD M. HEWLETT, 0F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC SVVITGH.

Application filed October 31, 1918.

To all arc/20m it may, concern.

Be it known that I. Flowann M. lsl nwnnr'r, a citizen of the United residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

My invention relates to electric switches and has for its object to provide an improved electric switch of the oil. break type.

The novel features which I believe to be characteristic of my invention, will be definitely indicated in the claims appended hereto, while the features of construction and mode of operation will be understood by reference to the following description taken in connection with the accompanying drawing which shows the preferred embodiment of my invention and in which:

Fig. 1 is a front elevation, paitly in section, of a switch embodying my invention and F ig. 2 is a top elevation of the switch shownin Fig. 1.

The switch embodying my invention, as shown in Fig. 1, comprises a metallic vessel 1, preferably of steel, and adapted to contain oil or other insulating fluid. Mounted within the vessel 1 are relatively movable cooperating contacts, separable beneath the surface of the fluid. Extending into the vessel 1, beneath the surface of the oil, are insulator terminal members, 2 and 3 for the switch, supporting at their lower ends the fixed contacts 4. Cooperating with the fixed contacts 4 is the movable 0r bridging contact 5, carried at the end of an insulated operating rod 6, which is operative with a reci iirocating motion by any suitable operating mechanism, not shown, to carry the movable contact 5 into and out of engagement with the fixed contacts 4 to control the circuit through the switch.

The vessel 1 is provided with. a cover member 7 to which the terminal members 2 and 3 are'secured and from which the vessel is removably supported, as will be described. This cover member 7 is preferablv a casting. provided with a downwardly projected portion or member 8 preferably integral therewith. Secured to the bottom of the member or wall 8, is a metal plate or member 9, preferably of steel,

Serial No. 260,455.

through which the terminal members 2 and 3 pass with slight clearance. The member 8 coincides in configuration with the top of: vessel 1 and is arranged to fit into the top of the vessel to substantially close the vessel except for the small openings in plate 9 around the terminal members 2 and The member 9 also cooperates with member 8 to provide an air chamber within the cover member. The cover member 7 is also provided with portions 10 which overhang or extend over the vessel 1 and slightly down the sides thereof. These overhanging portions are open at their lower ends to communicate with the air and are provided with chambers or pockets which communicate with the inner chamber of the cover 7 through openings 11 provided in the partition member 8. The openings 11 are provided' with battling means comprising a plurality of plates 11 having staggered openings therein to permit gases to escape therethrough but to prevent the escape of insulating fluid.

The vessel 1 is removably mounted or suspended from the cover member 7 by means of tie rods 12 passing" through the cover, preferably through the overhanging portions 10 and which'are removably secured at their lower ends to a cradle or supporting member 13 at the bottom of the vessel 1 and within which the vessel 15 carried. The supporting member 13 carries ears or extensions 1, as best shown in Fig. 2, between which the rods 12 extend. The lower ends of the rods also extend through members 1 1 which are detachablv secured to the cradle 18 but which serve to lock or -hold the rods 12 in engagement with the cradle. For detachably, securing the mem bers 14 to the cradle, 1 preferably make the members substantially L-shaped in configuration and provide in the cradle openings into which one end of the L-shaped members is inserted. Suitable locking nuts at the ends of the rods are then tightened to rigidly locl: and hold the cradle 13, Vessel 1 and cover 7 together. To remove the vessel 1 the nuts at the ends of the rods 12 are loosened whereby the locking members 14, together with the ends of rods 12, are movable free from the cradle 13. The cradle can then be removed, and the tank ill lowered or the cover removed therefrom by anv well known means.

It is well known that in the operation o't switches of the above character, that the separation of the contacts 4: and 5 under load, splashes oil and causes the evolution of a large volume of hot gases which, when mixed with air, torm explosive gaseous mix tures. These explosive mixtures are oi'ten ignited on further evolution of hot gases by the subsequent operation of the switch, causing explosions which frequently wrecl: the switch. By the novel construction ot my invention, I overcome these disadvantages by providing a practically closed vessel 1 of steel construction. The steel plate 9 substantially closes the vessel 1 causing the gases evolved, as the switch operates, to till the small air space in the vessel above the oil, in which space not enough air is mixed with the gases under usual conditions, to form explosive mixtures. Should explosions occur within the vessel under unusual conditions, the vessel 1 is of a construction to withstand the shocl: of such explosion without injury. These gases pass through the small openings in plate 9 surrounding the terminal members 2 and 3 and into the chamber provided by the cover member 7 and from this chamber pass out through the openings 11 and battles l1 into the pockets of the overhanging portions 10 and are then deflected downwardly away from the live parts of the switch into the air. The plate 9 furthermore prevents an excessive splashing of oil into the chamber of: the cover member 7 and the member 8 and bafiles 11 turther prevent the escape of any oil ejected into the chamber of the cover member. Should explosive mixtures occur within the chamber of the cover member 7 and become ignited such explosions merelv damage the cover member and the switch itself is unharmed. Should. under unusual conditions, explosions occur within the vessel 1., the rugged cover 7 and the cradle 13 held together b v tie rods 12 serve to enable the vessel. 1 to effectively resist the excessive strains and stresses due to such explosions. For switches of high current carrying capacity, the cover 7 and plate 9 are preferably made of non-magnetic metal.

lVhat I claim as new and desire o secure by Letters Patent ot the United States.

1. An electric switch coin 'irising a vessel adapted to contain an insulating lluid. rcla tivel movable contacts separable within the fluid in said vessel, cover tormei with passages tor the escape of gases formed at the opening oil the switch, and a plate sccured directl to said rover and arranged to protect the cover 'troin the Sll occurring at the separation of the contacts.

2. In a switch. a vessel ai lapted to contain insulating: fluid. contacts scparabh? within said fluid, a cover tor said vessel tormed o l? a casting having a depending wall, a plate adapted to protect said cover lroin the Hl u' i occurring at the opening of the switch. said plate being secured to said depending vall near its lower edge, anal means securing said cover to said vessel, said means being attached to the cover at a pointnear the upper portion oit' said depending wall.

3. The combination with a cover member having a downwardly extending member provided with openings. a metal plate scoured to the bottom of said downwardlv extending member to formv a chan'iber within said. cover, said cover having portions thereof enclosing said downwardly projecting member and provided with pockets communicating with said openings into said chamber and open below to the air. and a vessel adapted to contain oil removablv suspended t'rom said cover member and sub stantially closed by said plate.

a. An electric switch comprising a vessel adapted to contain an insulating fluid. relatively movable cooperating contacts separable in said fluid, a cover member for said vessel, and means for supporting said vessel from said cover comprising a cradle tor the. bottom of said vessel, tie rods having cl amping means th reon for connecting said cradle to said cover, said cradle having laterally opening slots for receiving said tie rods. and removable means engaging said cradle and the tie rods to prevent lateral movement of said tie rods.

In witness whereof, I have hereunto set my hand this 29th. day of October 1918.

EDWARD M. HEWLETT.

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